Metal tube bending machine



Sept. 12, 1944.

F. L. DUE R METAL TUBE BENDING MACHINE s Sheets-Sheet 1 Filed June 23, 1941 I IN VENTOR.

Sept. 12, 1944.

F. D UER METAL TUBE BE NDING MACHINE Filed June 23, 1941 3 Sheets-Sheet 2 m T m V m Sept. 12, 1Q. DUER METAL TUBE BENDING MACHINE Filed June 23, 1941 3 Sheets-Sheet 3 Patented Sept. 12, 19 44 UNITED STATE METAL TUBE ammo mourns Frederick Duet, ammo, nl. Application June 23, 1941, Serial No. 399,301 (01. 153-40)- 3 Claims. This invention relates to improvements in metal tube bending machines f the rotatable bending form character; having for an objectto provide a machine so constructed and operable as to permitof material quickening of the work of tube bending and afford considerably greater production. operating and maintenance economies. I

' justment of the materials to diiferent It is also an object of the invention to provide a metal bending machine which, by reason of the novel arrangement and predeterminable automatic adjustment or regulation of movement tive position of such clamp being also shown in dotted lines.

Figure 4 is an enlarged fragmentary horizontal section taken on line 4-4 of Figure 2; looking in the-direction in which the arrows point.

Figure 5 is an enlarged transverse section taken onlthe line 5-5 of Figure 2,1ooking in the direction in which the arrows point; and

Figure 6 is a perspective view of a particular form of chair frame, the structural tubing of which has been bent by the improved machine.

of rotatable bending forms, will operate to eflect rapid yet extremely accurate bending of tubes .or other materials to uniformly pattern duplicating-angular degrees,- hence insuring finished products possessed of overall corresponding formations. I

' Another object of the invention resides in providing the machine with adjustable mechanical means adjustable for automatically controlling or governing the extent of'movement of the re tatable bending forms.

A still further object of the invention is to provide the'machine with a durable and rugged work clamping device cooperable with the particulal'ly used rotatable bending form for per-' mitting the materials to be bent to be quickly yet securely clamped or locked in proper and accurate relationship to such bending form and as quickly moved to inoperative or released position to expedite rapid removal'of the bent materials fromengagement with the bending form or adpositions for additional bending operations.

Other objects of the invention will be in part obvious-and in part pointed out hereinafter.

Inorder that the invention and its mode of operation may be readily understood by-those skilled in the art to which it appertains, Ihav'e in the accompanying drawingsand the detailed.

description based thereupon, set out one embodiment of my invention. Inv the drawings:

Figure l is a plan view of the improved mashine with a partlbroken away.

Figure 2 is a side elevation of the same with a part of the illustrated supporting pillar broken away.

mitting rotary motion thereto, and the tube Havingmore particular reference to the drawings, in connection with which like characters of reference will designate corresponding parts throughout, the improved machine is provided with a supporting'frame which consists of a metal base I and an upright or supporting pillar 2 fixed to a portion thereof. p

.A horizontally disposed bed 3 is fixedly mounted, adjacent one end. as at l, to the upper end of the pillar 2, and receites and supports thereupon the working elements of the improved bending machine. The normally upper side of a the bed 3 has transversely disposed and relatively spaced pairs of guide plates I'adiustably s'ecured thereto through the medium of screws or bolts 6, and slidably receive rails or bars 1 therebetween. The rails 1, because of slidablereception between'thejpaired guide plates 5, ob-

viously, are capable of transverse sliding adjustment with respect to the bed 3. Screw-threaded rods! are arranged transversely of the bed 3 and have their screw-threaded shank portions engaged through brackets mounted on the outer side of said bed: adjusting nuts I! being turned into engagement with the brackets outwardly thereof and adapted to have bearing upon the same, for a purpose which will be subsequently described. Carried upon the normally inner end portions of the rails I is a longitudinally disposed bar ll, fixedly connected to adiacent portions of the rails by means of screws or bolts II. A sleeve or-tube ll provided adiacent its normally inner end with a laterally disposed finger. I4, is arranged upon the normally rearward end portion of the bar Ii, as shown in Figures 1 and 2, andis rigidly secured to said bar, as at it. It fixedly carries a laterally disposed bracket arm it upon its rearward end Figure 3 is an enlarged end elevation of the pompn' Upon the normally forward end: pormachine showing themountlng of vthe'form ree ceiving and supporting table, means for transtion of the rail carried bar ii, is a rotatably mounted and horizontally-positioned roller l'l, so located that it is substantially adjacent the forward end of the bed I.

holding clamp inoperative position, the 11102611 do vA secondary supporting or frame It, proadjacent portions of the plate.

vided with an extension or connection portion I9 is fixedly secured to the normally forward end of the bed 3. This secondary bed has a vertically disposed shaft 20 suitably journaled therein, preferably through the usage of antifrictional bearings, generally designated by the numeral 2|, and has a gear 22 spllned thereto over a portion of the same through a locking nut 23; the gear 22, obviously being disposed in a horizontal plane. The upper end of the shaft 291s extended above or beyond the upper side of the secondary frame It and is reduced, as at 24 and fixedly engaged through an appropriate opening formed in a horizontally positioned table 25, spaced from the adjacent upper side of said secondary frame and overlying a collar or plate 26. It. will be thus understood that with rotation of the shaft 20 and its gear 22, corresponding rotary motion will be transmitted to the table 25. The lower end of the shaft 20 is locked against vertical displacement with respect to the frame It! by engagement of a lock nut clamp and as will benoted, has its inner or work 20' on the screw-threaded lower end of the V same and having bearing upon an adjacent portion of said frame.

Disposed longitudinally of the bar I is a mandrel 21, the normally rearward portion of which is arranged in proximityto the tube l3 and has its end adjustably connected through and to the bracket arm l6 by engaging an adjusting nut 28 therewith. The remaining or forward portion of the mandrel 21, as will be noted upon reference to the Figures 1 and 2, extends to a point in proximity to the frame l8, serving as a guide and retaining means for tubing 29 to be bent by the machine. An adjustable stop 30 is slidably mounted on the mandrel 21 and is adapted to be secured in an adjusted position thereon through the medium of a locking screw 3|.

In order that the tubing 29 may be effectually bent to a predetermined angle or shape by usage of the improved machine, I provide a bendin form assembly retaining or receiving plate 32 on which a semi-circular peripherally grooved bending form 33 is fixedly mounted, said plate 32 and bending form 33 being provided with aligned openings through which aportion of the reduced upper portion 24 of the shaft 20 is received. The plate 32 thus arranged upon the table 25 and receiving the reduced upper'portion 24 of the shaft 20 therethrough, is fixedly secured to said table by engaging bolts or other suitable fastening devices therethrough and through adjacent portions of the table 25. In consequence, it will be is locked or otherwise secured to appropriate portions of the plate 32 by engaging bolts or similar fastening devices 35 therethrough and through The locating of the fixed clamping jaw 3 with respect to the bending form 33 is such tha its grooved work receiving and engaging face or side 34' aligns and is contiguous with the adjacent end of the peripheral groove of the bending form' 33. Relatively spaced and slotted fingers 36 are fixedly carried upon the normally outer or rearward side of the fixed clamp jaw 34 and receive the oppos te ends of a pivot pin 31 therein; the intermediate perengaging face grooved as at 40', to correspond to the grooved formation of the fixed clamp jaw 34. The jaw 40 is pivotally mounted between the extremities of a bifurcated operating lever 4|, as at 42 and, as will be noted, said lever is o angular formation whereby the outer or free body portion thereof will extend upwardly and away from the plate 32 for operation convenience; a handle 42' being carried by the outer portion of the lever to facilitate its usage or operation. Connecting links 43 are pivotally connected adjacent certain of their ends to the bifurcated or opposite sides of the lever 4| adjacent the elbow of itsangular formation, and the opposite or remaining ends of said links are pivotally connected to the remaining extremity of the substantially U-shaped body 38, as at 44. Pivotal movement of the operating lever 4| is adjustably limitable in one direction, by means of an adjusting stop screw 45 mounted upon an extension 46 integral with the normally outer portion of the body 38, i. e., that portion to which the links 43 are pivotally connected. Pivotal movement of said operating lever in the opposite direction is limited by means of a lug 41 fixed or integral with an appropriate portion of the body 33, so that when the lever handle 42' is grasped and pulled in an upward direction, the adjacent bifurcated portion of said lever 4| will be brought into engagement with said lug 41. Upon continued upward movement or pull of the lever 4| through its handle 42', it will be seen that the work clamp body 38 will be swung upwardly to a work disengaged or disengaging position, as shown in dotted lines in Figure 3 of the accompanyingdrawings. Assuming that the tubing 29 is properly arranged in the machine for bending, the work clamp body 38 is now swung downwardly to the position shown in full lines in Figure 3 and a continuing downward thrust is imparted to the handle 42' of the movable jaw operating lever 4|, resulting in the inward lateral movement of the movable clamp jaw 40 into positive clamping or gripping engagement with the adjacent surface of the tube 29 arranged or engaged in the grooved portion 34' of the fixed clamp jaw 34. In this way, it will be understood that the engaged or clamped portion of the tube 29 will be locked or fixedly positioned with respect to the bending form assembly and particularly, with relation to the bending form 33.

The extent of clamping engagement between the work clamp jaws 34 and 40, obviously, may be either increased or decreased by inward or outward adjusting of the adjusting screw 39 in or the corresponding opposite side portion of the fixed clamp jaw 34, as is clearly shown in Figure 3 of the accompanying drawings.

With a view toward providing means for im- 'and SI.

aasaara J 3- parting rotation to the shaft and hence, to the table and the bending form assembly carried thereupon, I horizontally mount a jack cylpositioned rack bar 54 extending longitudinally of and along one side of the machine bed 3. The normally forward portion of said rack bar 54 has its teeth meshing with those of the gear 22. Such meshing engagement is maintained by application of inward pressure to the bar from a guide or retaining roller supported in suitable jour- I stood that further movement of the rack bar 54- inan outward direction with respect to the cyllatter having been previously rotated to a position whereby to select a particular adjustable stop 58 for engagement with the bracket 59.

Upon such engagement of the bracket 53 with one of the adjustable stops 53, it will be underinder 49 will be checked or stopped and in consequence, that. thetransmission of rotary motion to the bending assembly will likewise be stopped and therefore, that the degree or angle of bend eifected by the machine through its bending form 33 will be controlled to the desired nicety. Obviously, by preselecting diflerent stops 58, movement of the rack bar 64 may be so modulated or. controlled as to effect bendsof different degrees or angles 'in the tubingbeing worked .upon or bent by th machine.

nal brackets upon an adjacent side of the secondary supporting bed or frame 18, as at 33.,

Thus with outward movement of the piston or plunger 52in its cylinder 49, correspondingmotion of the rackba'r 54 connected to said plunger will be transmitted to the. gear 22 mounted on the vertically disposed shaft 20, hereinbefore described.) Hence, this rectilinear motion of the" rack bar 34 will be transmitted to the shaft 20 as-rotary motion by reason of its being geared with the gear 22. By the same token, with movement of the piston ,or plunger 52 in its cylinder 49 in an opposite direction to that previously described. similar rotary motion will be imparted to the shaft 20. though in an opposite direction.

It is desirable that the extent of rectilinear movement of the rack 'bar' 54, in one direction, under urge or influence of the plunger 52 shall be limited or predetermined, whereby diilerent degrees or angles of bends may be effected in the tubing being worked upon in the machine; that is to say, the greater the extent of rotary movement of the shaft 20 and hence, the metal bending assembly, the greater the degree of bend imparted to the tubing being worked upon. To effect such predetermined limiting of movement of the rack bar 54, I rotatably mount a cylin- Val ved control mechanism, generally indicated by the numeral 6|, is preferably provided the cylinder 49 and such mechanism may be controlled by the machine operator through the medium of a control rod 62- connected to thevalve mechanism and extending therefrom to a point upon the machine convenient to its operator.

In operation of my improvedmachine, a length of tubing such as indicated by the numeral 29 is engaged over the mandrel 21 until the outer end thereof is brought into abutting engagement with the previously adjusted stop 30. .The mandrel engaged tubing is now contacted by the guide roller I1 and received in a portion of the grooved peripheral surface of the bending form 33. With attainment of the proper positioning of the tubing 29, the work clamp is now swung from its I inoperative position as shown in dotted lines in into gripping or clamping engagement with the drical body 51 upon a lower portion of the secondary bed or frame I! 'in proximity to the normal path of travel of the rack bar 54. "with the disposed andoutwardly extending. screw-threadtubing 29 outwardly of. the bending form as will.

be clampingly connected to the bending 'form 33 ed steps or bolts, generally designated by the tances from the adjacent side or end of the body 51, thus, causing them to be arranged in relatively stepped relation to each other. Engageable with the rack bar 54 is a substantially U- shaped bracket 59, one side of which is provided with inwardly disposed teeth 59' adapted to be engaged with the teeth on the inner side of the rack bar 54 and to be adjustably or releasably retained in such engagement by means of lockingscrews 30. Accordingly, with inward turning of the screws 33, the U-shaped-bracket 59 will be fixedly secured in a particularly adjusted posi-- tion or relation upon the rack bar 54. This adjusted positioning of the bracket 59. upon the rack bar 54 is such that a portion thereof, with rectilinear movement of the rack bar 54 in one direction, will be brought into abutting engagement with the uppermost or preselected adjustand likewise, through-the work clamp to the plate 32 fixedly connected to the rotatable table 25. The valved control mechanism of the cylinder 49is now actuated so as to cause the plunger .52 working therein to be moved outwardly or toward-the bed 3, imparting rectilinear motion to the'rack bar 54, which, by reason of its being intergeared with the gear 22 will eflect rotation of the shaft 20, the table 25 and the tubebending assembly comprised of the plate 32, the bending form 33 and the work clamp. Such rotation peripheral surface of the bending form 33. The degree or angle of bend made in the tubing 29,

as hereinbefore described, will be controlled or regulated according to the particularly preselected adjustable stop 53 and the resultant control of travel or extent of travel of the rack bar 34 under urge of its particular operating means. With the bend made, the work clamp isreleased; the tubing 29 readjusted. for further bending;

the rack bar 54 returned to its initial or starting position together with the tubebending assemg bly, whereupon the work clamp is reengaged with: able stop 53 carried by the rotatable body 5.1; the II the now properly adjusted or readjusted tubing lengths of working strokes of the rack bar 54 may be effected and that through the latter, difierent degrees of bends in the tubing being worked upon by the machine may be eflected,

such as conditions 'or preference may dictate. Also, it will be understood that by reason of the laterally adjustable mounting of the longitudinally disposed bar ll upon the machine bed 3,

through the rails 1, a wide range of lateral adjustment of the mandrel 21 supported by said bar II will be permitted with relation to the particular metal bending assembly carried upon and fixedl connected to the rotatable table 25,

I claim:

1. A bending machine, including a bed, a horizontal supporting bar,'a mandrel carried by and disposed longitudinally of the bar, means supporting said bar received upon and transversely adjustable of said bed, a vertically disposed shaft journaled in bearings supported by the bed having its upp r end extended above said bed, a gear on the shaft, drive means supported on the bed in spaced relation to said shaft and gear, a rack bar fixedly connected to said drive means disposed longitudinally oi the bed meshing with said gear, a plurality of movably supported independently adjustable stops on the bed selectively movable into positions in the path of travel of said rack bar, a bracket adjustable along saidrack bar engageable, at times,.with a particularly selected adjustable stop, and bending means removably engaged with the extended end 013- said shaft and rotatable thereby.

2. In combination with the work bending form of a metal bending machine, a substantially inverted U-shaped clamp body pivotally mounted in proximity to one side of said form, a fixed clamp jaw in proximity to the pivotally mounted portion of said body, an operating lever having an angularly formed inner portion, means pivotally connected to the opposite side of said body and to said operating lever adjacent the elbow of its angular formation, a movable clamp jaw connected to said lever and arranged in opposed relationship to said fixed clamp Jaw, and adjustable stop means on the free side oi said body engageable with said lever for limiting pivotal movement thereof in one direction;

3. In combination with the work bending form of a metal bending machine, a clamp body pivotally mounted in proximity to and in cooperative relation with said form, an adjustable clamp jaw in proximity to the pivotally mounted portion of said body, an operating lever, means swingably connecting said lever to the opposite side of said body, a clamp jaw pivotally connected to said lever in opposed relation to said lever in opposed relation to the first mentioned clamp jaw and slideable with respect to said body, and adjustable means on said opposite side of the body engageable with said lever, at times, for limiting' 

